Has humanity reached ‘peak intelligence’?
bbc.com
bbc.com
You have many billions of people alive who have had this happened to them.
Then toss in the other things that reduce IQ post infancy.
Lot of scope for worldwide improvement.
Looking at the top countries is a different important. But understanding the Flynn effect would be step one which isn't happening. There don't even seem to be any theories. When you can't even find crackpots YouTube talking about it, there's an issue.
Perhaps sound wouldn't be the right medium to carry it?
Or alternatively, perhaps only those with <various> enhancements could transmit/receive it?
However, I can't fathom this having an evolutionary impact. It is awfully difficult to fail so hard at being a consumer that you don't make it to your reproductive years, right?
So, yeah, everybody knows about the linkage, but it should make you stop and consider that it would make you expect the opposite of the claim above.